1998 Hyundai Coupe FX (Tiburon) warm start problem

Hi

I have a 1998 Hyundai Coupe FX (Tiburon) with a warm start problem,
when the car has reached operating temperature, if it is switched off,
it will not restart until it has cooled down.

It's the 1.6 engine version.

This problem began happening a few weeks ago, but is really only
noticable on multiple short journeys. On the road, it seems to run
fine, although the idle is a little rough & it stumbles at idle
sometimes.

Today, I let it warm up & noticed during the warm up phase, at one
point it appeared to stumble, almost cut out, then recovered, then
carried on as normal. When I switched it off, then on, it would not
fire up.

Cranking is fine, but there are no sparks at the plugs.

The coil seems OK, resistance wise, the plugs were changed recently.I
suspect some defective sensor is preventing the ECU from driving the
coil.

I had a look at the Hyundai tech pages, nothing exactly like this
problem, although they do say the crank sensor might be a reason for a
no start condition. The camshaft sensor is also a potential failure
point.

A Google search turned up lots of starting problems, but nothing
related to temperature.

The car starts first time from cold, every time.
Has anybody seen anything like this before?

Which sensor is not critical, as one seems to cut out when hot, but
the engine runs anyway?

Where exactly is the ECM (ECU)located?

Thanks

Gerryo

 

Use chill spray to see if it's defective.

 

exactly the same problem with my 1998 Accent!

Phil

 

It's going to the Hyundai dealers today, I'll post the results when available.

Gerryo

 

I'm looking forward to finding out! thanks

Phil

 

Since the problem seems to be heat related, possible that the fuel is
boiling somewhere in the fuel system near the engine, causing a vapor
lock condition.

 

I had exactly the same problem on my son's '94 Scoupe with the 1.5 engine.
The coolant temperature sensor was bad.

This was located in the thermostat housing. There were 2 sensors mounted
there. The coolant sensor was the lower of the two.

The car can't sense the engine is warmed up and is basically flooding the
engine with too much gas.

 

in this case, did the computer store a trouble code? and did you smell gas
when this was happening?

Phil

 

Yes. That's how I tracked it down. I don't remember any unusual gas smell.

 

Got the car back this evening, it was the crank sensor.

Job cost Euro 177 ( approx. $210 or £124).
Sensor cost was Euro 74 (approx. $88 or £52).

Interesting reading on the garage report, there were no fault codes
revealed by the diagnostics, nothing stored in the ECU.

However, the following is from the Hyundai diagnostic trouble code
list...

Code Problem
P0335 Crankshaft position sensor circuit malfunction
Crankshaft Position Sensor

P0336 Crankshaft position sensor circuit range

Wonder why none of these was stored, seems like it should have been
P0335 at least.

Gerryo